1. Field of the Invention
This invention concerns control systems for operating blowout preventers used in well drilling operations for closing off around drill pipe and the like extending through the blowout preventer bore or for closing the blowout preventer bore itself if no pipe extends through it. More specifically, it pertains to an improvement which provides an emergency closing system connected into a conventional blowout preventer control system and which can be operated to close the blowout preventer should the control system malfunction and not operate.
2. Description of the Prior Art
Conventional blowout preventer control systems include an operating power fluid supply unit for opening and closing the blowout preventer. It is usually remotely located from the drilling rig floor. The operating power fluid is conveyed from the supply unit through an opening conduit and a closing conduit to the opening and closing chambers, respectively, of the blowout preventer. The blowout preventer is normally in the open position during drilling operations and is closed when a blowout is suspected or occurs. Should it become necessary to close the blowout preventer and the conventional control system malfunctions, no independent means are provided to supply operating power fluid to close the blowout preventer. Some systems provide alternate means for routing fluid to the blowout preventer but all are dependent on a common, not independent, operating power fluid supply source. There is a need for an emergency power fluid system to ensure closing of the blowout preventer which is connected into the conventional blowout preventer control system, is capable of being operated quickly, and has its own operating fluid supply source which is completely independent of the power fluid supply source of the conventional system. The independent operating fluid supply and valves for controlling the flow thereof into and from the conventional system are preferably located remote from the drilling rig floor to permit accessibility in case of fire or other dangerous conditions on or near the rig floor during a sudden blowout.